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H. JANDER.

APPARATUS FOR THE RECOVERY OF ARSENIOUS AND SELENIOUS OXIDS. APPLICATION FILED APR.3.1919.

1 ,32 1 ,2 1 1. Patented Nov. 11, 1919.

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HENRY JANDER, OF BROOKLYN, NEW YORK;

APPARATUS FOR THE RECOVERY or AnsEnIoUs AND sELENIoUs oxrns.

Specification of Letters Patent.

Patented Nov. 11, 1219.

Application filed April 3, 1919. Serial No. 287,262.

carrying out the process for the recovery of selenlous and arsenious oxide as a byproduct resulting from the burning ofa pyr te.

Sulfur, selenium and arsenic are relative.

elements and are always found associated in a more or less degree; they are combusti-' ble and form oxids when burned in free oxygen, to wit:

SO +SeO +As O Owing to the difference in their atomic weight, they form gases of different specific gravities. It is in the form of oxids where selenium, arsenic and sulfur commence to diverge. When the burner gases from the pyrite are led into a chamber and allowed to cool, to about 200 degrees C., the arsenious oxid crystallizes and precipitates in the* form of a fine dust. If these gases are cooled to a somewhat lower degree, selenious oxid will be precipitated, but the sulfurous oxid being a more stable" gas, under ordinary atmospheric pressure and temperature, will remain floating in the chamber. If this aseous sulfurous oxid is -carefullydrawn rom the chamber and led into a flask containing hot water mixed with nitrlc acid, the following reaction will take place:

When drawing the sulfurous gases ofi' care must be taken not to agitate the selenious and arsenious oxids, or they will become mixed with the sulfurous gases, thereby couof arsenic and seleniumwill be recovered as by -lproducts.

Y O my scribed, said operations being an epitomized recitation of my improved process, I have designed a special apparatus. to carry out the steps of the process.

'bod-ying the elements out the operations above de-.

In the accompanyingdrawings, which.

form a part of thisspecification,

Figure 1 is a sectionalv 'ew of a refrig crating apparatus within which theburner gases from the pyrite burner are coole d down to produce the resultsdescribed Fig. 1s a similar view o'f -an o venor}, mufiie within which the sulfurdioxid, which has been liberated in the refrigerator, -is reheated and then mixedjwith nitric acid 55 fumes;

The apparatus of a suitable housing 3 containing .coolirig or refrigerating cells 4, '5, 6, 7 and 8, and a. 1 pyrite burner 9 ofany suitable'construction. The pyrite burner 9 is. connected to cell 4 by apa'ssage 10. Cell 4. is connected to cell 5 by a passage 11, said passage being located ad acent the upper end-of said cells. Cells 5 and .6 are connected by passage 12 nearthebottoms'thereof, cells 6 and 7 and cells 7 and 8 being likewise connected,- by passages 13 and.14=, respectively A-further element of the apparatus consists of a reheating oven 16 having ain'ain- 8'0" flue 17 surrounded by smaller flues or tubes 18 placed in communication with a fire-box 19 and a chimney 20. The main flue 17, is connected by a passage 2l with a chamber 22 containing a pot orcontainer 23 for diluted nitric acid. The chamber 22 is conmated by passages 24- 'and 25 with a Glover tower (which is not shown). The reheater' 16 may be of any desirable construction emhence'a detailed description of the herein "illustrated reheater will be omitted.

The method of recovering selenious and arsenious oxids Wlll now be explained.

, Pyrites will be placed in burner 9 and transformed into gases by the application of heat. The gases thus generated will pass through duct or passage 10' into the lower portion 26 of the cooling cell-4 which-contains cooling coils 27 through which brine is forced.

The gases as they-rise and pass through the coils will be cooled to about five hundred and thirty degrees centigrade. The gases will now pass through passage 11 into cell 5, thence down through the cooling pipes 28, which also contain brine, intothe lower chamber 29,.thence into the lower chamber A of cell 6 up through cooling pipes 30, Where their temperature will be reduced to about 200 C. This cooling action will cause the herein illustrated consists above described 90 precipitation of the arseniousoxid in the form of dust which will settle on the bottom of the chamber. The unprecipitated gases will pass through passage 13 into cell. 7, thence downward through cooling coils 31, containing brine, into lower chamber 32 of cell 7; thence through passage 14: into cell 8, thence upward through cooling coils 33. When the gases have reached'this point they will have been cooled to about one hundredand fifty degrees C. causing the precipitation of selenious oxid. The remaining gas, Sulfurous oxid, will flow into duct .or passage 15, thence into the main flue 17 of the reheater 16. The sulfurous oXid (S0 contained in duct 17, will be reheated by the hot gases in the circulating flues 18 which emanate from the fire on the grate in the fire-box 19. The reheated SO will pass through the passage 21 into chamber 22 containing pot 23, which in turn is charged with a solution of water, and nitric acid, the fumes of which will mix with the S0,, The following reaction will now take place:

or in other words, three volumes of sulfur dioxid plus two volumes of nitric acid plus two volumes of water=three volumes sulfuric acid gas plus nitrousoxid. These resuiting gases pass throu h assages 24 and 25 into a Glover tower (no t shown), after which they will be subjected to the usual process for producing sulfuric acid.

It would be noted that while the S0 is passing through the reheater it never comes thereto, cooling means in each cell, and a reheating device connected with one of the cells' 2. In an apparatus for the recovery of arsenic and selenium, a pyrite burner, a refrigerating device and a reheating device consisting of a main flue, means to cause hot gases to circulate around said flue exteriorly thereof, a chamber in communication with .the main flue, andmeans to contain an acid located in said chamber.

3. In an apparatus for the recovery of arsenic and selenium, a plurality of intercommunicating chambers, coils located within and intermediate the top and bottom of each chamber adapted for the passage therethrough of a refrigerant, and a reheating device connected with one of the chambers.

Signed at New York city, N. Y., this 1st day of April, 1919.

HENRY J ANDER.

Witnesses:

EDWARD A. JARVIS, MAURICE BLOCK. 

